Our overall goal is to develop a method for controlling a multiple joint artificial arm. Specifically we are seeking to define equations which can establish the intended motion of an amputee's missing arm based on small electrical signals which are generated by a selected set of intact shoulder muscles. For example, the electromyographic (EMG) signals generated by ten shoulder muscles are used as inputs to a set of controller equations. The controller equations operate on the input to determine the torque levels which should be applied to the joints of the prosthesis. The second goal of our project is to contribute fundamental knowledge in the area of biomechanics. We are in an excellent position for such a task since we are currently developing an extensive experimental data base which relates to human neuromusculoskeletal performance. The data base, when used with an analytically rigorous methodology, greatly facilitates interpretation and representation of results. For example, we are currently producing very interesting information in the following areas: 1. Quantitative functional musculoskeletal anatomy. 2. The relationships between muscularly generated torques and cutaneously measured electromyographic signals. 3. Patterns of coordination of multiple, redundant muscles of the arm and shoulder.